Process of producing fermentable sugars.



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FRANCIS GALLAGHER, OF NEWTON, MASSACHUSETTS, ASSIGNOR'TO STANDARD ALCOHOL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF MAINE.

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No Drawing.

To all whom it may concern Be it known that I. F n'A'xois E. GAL- LAGHER, a citizen of the United States, reside ing at Newton, in the county of Middlesexand State of Massachusetts, have invented certain new and useful Improvements in Processes of Producing Fermentable Sugars, bf-which the following is a specification;

,T;his invention relates to the production Qfiffermentable sugars from ligno-cellulose mother cellulosic raw material.

"It is Well known'that certain constituents of such cellulosic raw materials assawdust, wood-waste, etc., are convertible, in presence of dilute acids or suitable hydrolyzing agents, into fermentable sugars. The cookliiigor digesting of the material is prefereffected in closed di'gesters by the direct fiction of steam under suitable pressure, and

may be performed under any suitable conditions. -The cooked mass is then extracted with Water, preferably in a diffusion apparatus, and the extract is neutralized, fortified with nitrogenous material, seeded with yeast, fermented and distilled for the production of alcohol. The above steps may be carried out in any manner known to the art. The

liquidresidue of the distillation is known inthe art as i spent wort or slop, and contains in solution a variety of'substances derived from the-original ligno-cellulose by hydrolysis. Thus the slop may contain: (1)

Bodies which are not directly fermentableand are not convertible by hydrolysis into fermentable substances. (2) Bodies which, While not directly fermentable, are convertible by hydrolysis into fermentable substances,-

so-call ed wood-dextrins. (3) Decomposition,

productsof dextrose. I have found that from the original ligno-c'ellulos'e may be ob tained by subjecting this slop to further h drolysis. However, since the hydrolyzab e constituents of the slop consists principally, if not exclusively, of dextrin-like bodies, herein referred to as wood-dextrins, 'it is found essential for the best results, to modify somewhat the conditions whichai'e applicable to the hydrolysis of the original ligno-cellulose. v

Excellent, results have been secured by proceeding as follows: An amount ofhy-I drolyzing acid, say sulfuric or hydro-chloric acid, equivalent to about two per cent. by weight of the sawdust to be digested, is di- Specification of Letters Patent.

Patented'Ma-r. 24, 1914.

Application filed ul 15, 1912, Serial No. 709,55.

luted by adding thereto a suitable proportion of slop, and this acidified slop is mixed w th the l1gnocellulose and the whole sublnitted to a process of digestion or cooking. The slop may be somewhat concentrated if desired, either before or afterthe addition of the acid, and is preferably added in the proportion of ten to fifteen per cent. of

solids in the slop by weight of the dry lignocellulose, although .a larger or smaller percentage may be used. The digestion is best performedundermoderate pressure of steam, sixty to ninety pounds per square inchhaving been found suitable. By proceeding in this manner, an extract may be obtained which contains fermentable constituents derived both from the ligno-cellulose and from-the slop.

Inasmuch as the slop contains considerable quantities of calcium compounds and other constituents which are capable of reacting with or neutralizing sulfuric acid, it is desirable to add to the slop a materially larger quantity of acid than would suffice for the hydrolysis of the ligno-cellulose alone. .For example, an addition of one- -half to one per .cent. of. sulfuric acid by weight of ligno-cellulose is suflicientto bring about a vigorous hydrolysis under proper temperature conditions. but when the slop is The amount of acid'added should in all cases be such that .there remains a substantial excess of free hydrolyzing acid, after the calcium-organic'salts ofthe slop have been decomposed.-- a substantial increasein the yield of. alcohol-;'

In some cases it is desirable to'subject the ligno-cellulose to digestion at a temperature higher than is best suited for the slop, and

in :such cases the procedure may be corresuitably acidified, may be boiled or heated -'by itselfyor admixed with the extract from spo-ndi'ngly modified. For example, the slop,

stage of. the process where hydrolysiswill 11o occur under the existing temperature conlosic raw material, the step which consists in subjecting thespent Wort, in admixture with cellulosic raw material, to a furtherhydrolytie treatment.

'3. In a process of producing fernien'table =-sugars from ligno-cellulose or other cellulosic raw material, the step which COHSIStS in subjecting the spent wort, in admixture with the soluble products resulting from the h drolysis of the cellulosic raw material, to a 'urther hydrolytic treatment.

j In testimony whereof Iaflix my signature in presence of two witnesses.

FRANCIS E. GALLAGHER.

Witnesses:

ARTHUR D. LITTLE, AMY MONTGOMERY. 

